Wednesday, 6 June, 2012, 16:16
In May due to upcoming EMAS workshops, effort was done to prepare more zinc samples in order to confirm previous observations and collect proper amount of data for statistics. Unfortunately as previous EBSD observations revealed, preparation of zinc samples in a way that no distortion to the crystalline lattice and no twins are introduced is considerable problem and cannot be carried out in short time span. This is true especially for preparation of samples from non deformed zinc (initial state) which is generally softer and quite easily deformed during cutting and grinding. Introduced layer of deformation with deformation twins is then extremely hard to remove during mechanical polishing as affected layer can have thickness up to hundreds of micrometers (at least one grain layer). Partial solution to this problem is removal of deformed and twinned material during chemical etching. This method is faster and does not introduce additional deformation, however it also does not produce flat, even surface. This is due to differences of etching speed of crystals in different orientations, as well as much faster etching of grain boundaries. Because of this etching has to be followed with careful grinding on 2500 SiC grinding paper in order to remove topography and produce surface suitable for EBSD analysis.